Photovoltaic

The first practical conversion of light into electrical energy was in 1954 using a silicon solar cell. It used the photo-electric effect first observed by Antoine Cesar Becquerel and his son Alexandre Edmond Becquerel in 1839: the emission of electrons from a surface (usually metallic) upon exposure to, and absorption of, electromagnetic radiation (such as visible light and ultraviolet radiation). This effect is the basis for a further conversion of the absorbed energy into electrical energy within a solar cell. There has been an enormous growth in solar photovoltaic installations in the last two decades and they will play an important role as one alternative to dwindling fossil-fuel energy resources.